CEL Driving me Insane!

[Jstcruz]

I keep getting the 171 and 174 lean codes popping up. I have replaced all of the intake gaskets and looked over all of the vac lines. Every once in a while the cel comes on with those codes, I'll turn it off with my ScanGauge and the light stays off sometimes for a couple hundred miles. Some times it will come on several times a day, sometimes not for a couple days.

Is there something going on that causes a lean condition for an instant? Just long enough to trigger the cel then the condition is no longer there? I am getting better than ever milage, its running great. The idle isnt perfect but its not bad. What kind of thing might cause this?
Thanks in advance for your help!

Mods include headers, delete 1 cat, flowmaster, open cone filter adapted to MAF, new o2s

 

[Tbars4]

...Here are the items to look at...

A) Not the o2 sensors

1) Probably Vacuum leak
2) Clean the MAF
3) EGR tube leak
4) Plugs and wires

OR 5) Intake manifold gaskets

..IIRC there was an issue with running cone filters on the second gens causing these codes and also look at the air tube between the MAF and the Throttle Body...There are a couple thread's on it somewhere here..

 

[Jstcruz]

...Here are the items to look at...

A) Not the o2 sensors

1) Probably Vacuum leak
2) Clean the MAF
3) EGR tube leak
4) Plugs and wires

OR 5) Intake manifold gaskets

..IIRC there was an issue with running cone filters on the second gens causing these codes and also look at the air tube between the MAF and the Throttle Body...There are a couple thread's on it somewhere here..

I learned that the o2s were not an issue after replacing them, I didnt need that $$ anyway (yeah right)
I have cleaned the maf, all of the gaskets in the top end are new, plugs and wires are fairly new and I put an original air box back on it to test the theory with no changed results.

I will definatly recheck this tho, I never inspected the air tube. I have cleaned and inspected the egr stuff tho. I was getting some egr code that pointed to the egr senser thing being clogged so i replaced that.

 

[Tbars4]

..Be sure to go over all the vacuum lines again and triple check them at the bends, Brake vacuum grommet, PCV grommet, EGR vacuum hoses, etc...

..If the air tube has a pin hole or if the clamps are not tight, (same as if you have a crack in a vacuum line) When you get on the throttle either for torque or power, enough extra air will get in to throw that code...

..I've caught these issues easily and I'm the Hero...I've gone over these same issues multiple times and finally found the problem making me fell like an idiot for the prior attempts..

...I've had the best luck on finding the resolve to this problem when I've got all the time in the world and on a day when I have nothing better to do than find this problem...

..Oh yea..MAF's do go bad even though they test with a voltmeter good...